The installation and maintenance of the gate valve should pay attention to the following matters

1. Handwheels, handles and transmission mechanisms are not allowed to be used for lifting, and collisions are strictly prohibited.
　　2. Double gategateIt should be installed vertically (that is, the valve stem is in a vertical position and the handwheel is on the top).
　　3. The gate valve with bypass valve should be opened before opening (to balance the pressure difference between the inlet and outlet and reduce the opening force).
　　4. Belt drive mechanismgate, Install in accordance with the product manual.
　　5. If the valve is frequently opened and closed, lubricate at least once a month.
The main standard manual knife gate valve
　　(1) GB12232-89 "General Valve Flange Linked Iron Gate Valve"
　　(2) GB12234-89 "General Valve Flange and Butt Welding Steel Gate Valve"
　　(3) GB8486-87 "General Technical Regulations for Internal Thread Connection of Gate Valves, Stop Valves, Ball Valves and Check Valves"
　　(4) GB8465.1-87 "Internal thread connection gate valve, cut-off valve, ball valve, check valve basic size iron gate valve"
　　(5) JB/T53162-94 "Gate Valve Product Quality Classification"
　　(6) JB/T5298-91 "Steel Flat Gate Valve for Pipeline"
　　(7) JB/Z243-85 "Gate Valve Static Pressure Life Test Procedure"
　　(8) JB/TQ648-88 "Iron Wafer Flat Gate Valve"
　　(9) JB/T53200-94 "Quality Classification of Iron-based Flat Gate Valve Products"
　　(10) JB/T53242-94 "Quality Classification of Steel Flat Gate Valve Products"
　　1 Principle
　　The closing piece (ram) moves along the vertical direction of the center line of the passage for full-open and full-close cutting.
　　2. Selection
　　gateMainly used to cut off or connect the medium in the pipeline, generally not used as adjustment or throttling.
　　3. Classification
　　gateAccording to different classification methods, it can be divided into: parallel gate valve, wedge gate valve, lift gate valve, rotating rod gate valve, fast opening and closing gate valve, narrow gate valve, flat gate valve, etc.
　　4. Features
　　The fluid resistance is small, the applicable pressure and temperature range is large, the medium flow direction is not restricted, and the sealing performance is good.
　　5. Key points of construction and installation
　　1) The installation position, height, and direction of inlet and outlet must meet the design requirements, and the connection should be firm and tight.
　　2) The handles of all kinds of manual valves installed on the thermal insulation pipeline must not be downward.
　　3) Visual inspection must be carried out before the valve is installed, and the nameplate of the valve should comply with the current national standard "General Valve Marking" GB 12220.For valves with a working pressure greater than 1.0 MPa and a cut-off function on the main pipe, the strength and tightness performance test shall be carried out before installation, and the valve shall be used only after it is qualified.During the strength test, the test pressure is 1.5 times the nominal pressure and the duration is not less than 5min. The valve housing and packing should be qualified without leakage.During the tightness test, the test pressure is 1.1 times the nominal pressure; the test pressure should meet the requirements of the GB 50243 standard during the test duration, and no leakage on the valve flap sealing surface is qualified.Concealed rod wedge cast iron gate valve
　　4) The hand wheel, handle and transmission mechanism are not allowed to be used for lifting, and collision is strictly prohibited.
　　5) The gate valve with transmission mechanism should be installed according to the product manual.
　　6. Implementation standards
　　1), product standards
　　"General valve flange connection iron gate valve" GB/T 12232-2005
　　"General Requirements for Steel Valves" GB/T 12224-2005
　　'Steel flat gate valve for pipeline》JB/T 5298-91
　　"Valve Inspection and Testing" JB/T 9092-1999
　　"Safety Evaluation Standards for Drinking Water Delivery and Distribution Equipment and Protective Materials" GB/T 17219-1998
　　2), engineering standards
　　"Code for Construction Quality Acceptance of Building Water Supply and Drainage and Heating Engineering" GB 50242-2002
　　"Code for Construction Quality Acceptance of Ventilation and Air Conditioning Engineering" GB50243-2002